" Maintainer:   Bram Moolenaar <Bram@vim.org>
" Last Change:  2022 Mar 17

if exists("b:current_syntax")  | finish  | endif

let s:cpo_save = &cpo  | set cpo&vim

let s:ft = matchstr(&ft, '^\([^.]\)\+')

" check if this was included from cpp.vim
let s:in_cpp_family = exists("b:filetype_in_cpp_family")

" Optional embedded Autodoc parsing
" To enable it add: let g:c_autodoc = 1
" to your .vimrc
if exists("c_autodoc")
    syn include @cAutodoc <sfile>:p:h/autodoc.vim
    unlet b:current_syntax
endif

" A bunch of useful C keywords
syn keyword     cStatement      goto break return continue asm
syn keyword     cLabel          case default
syn keyword     cConditional    if else switch
syn keyword     cRepeat         while for do

syn keyword     cTodo           contained TODO FIXME XXX

" It's easy to accidentally add a space after a backslash that was intended
" for line continuation.  Some compilers allow it, which makes it
" unpredictable and should be avoided.
syn match       cBadContinuation contained "\\\s\+$"

" cCommentGroup allows adding matches for special things in comments
syn cluster cCommentGroup   contains=cTodo,cBadContinuation,@In_fancY

" String and Character constants
" Highlight special characters (those which have a backslash) differently
syn match       cSpecial        display contained "\\\(x\x\+\|\o\{1,3}\|.\|$\)"
if !exists("c_no_utf")
    syn match     cSpecial        display contained "\\\(u\x\{4}\|U\x\{8}\)"
endif

if !exists("c_no_cformat")
    " Highlight % items in strings.
    if !exists("c_no_c99") " ISO C99
        syn match   cFormat         display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlLjzt]\|ll\|hh\)\=\([aAbdiuoxXDOUfFeEgGcCsSpn]\|\[\^\=.[^]]*\]\)" contained
    else
        syn match   cFormat         display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlL]\|ll\)\=\([bdiuoxXDOUfeEgGcCsSpn]\|\[\^\=.[^]]*\]\)" contained
    endif
    syn match     cFormat         display "%%" contained
endif

" cCppString: same as cString, but ends at end of line
if s:in_cpp_family && !exists("cpp_no_cpp11") && !exists("c_no_cformat")
    " ISO C++11
    syn region    cString         start=+\(L\|u\|u8\|U\|R\|LR\|u8R\|uR\|UR\)\="+ skip=+\\\\\|\\"+ end=+"+ contains=cSpecial,cFormat,@Spell extend
    syn region    cCppString      start=+\(L\|u\|u8\|U\|R\|LR\|u8R\|uR\|UR\)\="+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=cSpecial,cFormat,@Spell
elseif s:ft ==# "c" && !exists("c_no_c11") && !exists("c_no_cformat")
    " ISO C99
    syn region    cString         start=+\%(L\|U\|u8\)\="+ skip=+\\\\\|\\"+ end=+"+ contains=cSpecial,cFormat,@Spell extend
    syn region    cCppString      start=+\%(L\|U\|u8\)\="+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=cSpecial,cFormat,@Spell
else
    " older C or C++
    syn match     cFormat         display "%%" contained
    syn region    cString         start=+L\="+ skip=+\\\\\|\\"+ end=+"+ contains=cSpecial,cFormat,@Spell extend
    syn region    cCppString      start=+L\="+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=cSpecial,cFormat,@Spell
endif

syn region      cCppSkip        contained start="^\s*\(%:\|#\)\s*\(if\>\|ifdef\>\|ifndef\>\)" skip="\\$" end="^\s*\(%:\|#\)\s*endif\>" contains=cSpaceError,cCppSkip

syn cluster     cStringGroup    contains=cCppString,cCppSkip

syn match       cCharacter      "L\='[^\\]'"
syn match       cCharacter      "L'[^']*'" contains=cSpecial
if exists("c_gnu")
    syn match     cSpecialError   "L\='\\[^'\"?\\abefnrtv]'"
    syn match     cSpecialCharacter "L\='\\['\"?\\abefnrtv]'"
else
    syn match     cSpecialError   "L\='\\[^'\"?\\abfnrtv]'"
    syn match     cSpecialCharacter "L\='\\['\"?\\abfnrtv]'"
endif
syn match       cSpecialCharacter display "L\='\\\o\{1,3}'"
syn match       cSpecialCharacter display "'\\x\x\{1,2}'"
syn match       cSpecialCharacter display "L'\\x\x\+'"

if (s:ft ==# "c" && !exists("c_no_c11")) || (s:in_cpp_family && !exists("cpp_no_cpp11"))
    " ISO C11 or ISO C++ 11
    if exists("c_no_cformat")
        syn region  cString         start=+\%(U\|u8\=\)"+ skip=+\\\\\|\\"+ end=+"+ contains=cSpecial,@Spell extend
    else
        syn region  cString         start=+\%(U\|u8\=\)"+ skip=+\\\\\|\\"+ end=+"+ contains=cSpecial,cFormat,@Spell extend
    endif
    syn match     cCharacter      "[Uu]'[^\\]'"
    syn match     cCharacter      "[Uu]'[^']*'" contains=cSpecial
    if exists("c_gnu")
        syn match   cSpecialError   "[Uu]'\\[^'\"?\\abefnrtv]'"
        syn match   cSpecialCharacter "[Uu]'\\['\"?\\abefnrtv]'"
    else
        syn match   cSpecialError   "[Uu]'\\[^'\"?\\abfnrtv]'"
        syn match   cSpecialCharacter "[Uu]'\\['\"?\\abfnrtv]'"
    endif
    syn match     cSpecialCharacter display "[Uu]'\\\o\{1,3}'"
    syn match     cSpecialCharacter display "[Uu]'\\x\x\+'"
endif

"when wanted, highlight trailing white space
if exists("c_space_errors")
    if !exists("c_no_trail_space_error")
        syn match   cSpaceError     display excludenl "\s\+$"
    endif
    if !exists("c_no_tab_space_error")
        syn match   cSpaceError     display " \+\t"me=e-1
    endif
endif

" This should be before cErrInParen to avoid problems with #define ({ xxx })
if exists("c_curly_error")

    syn match cCurlyError "}"
    syn region    cBlock   start="{" end="}" fold contains=ALLBUT,
                                                     \cBadBlock,
                                                     \cCurlyError,
                                                     \@cParenGroup,
                                                     \cErrInParen,
                                                     \cCppParen,
                                                     \cErrInBracket,
                                                     \cCppBracket,
                                                     \@cStringGroup,
                                                     \@Spell
else
    syn region    cBlock   start="{" end="}" fold transparent
endif

" Catch errors caused by wrong parenthesis and brackets.
" Also accept <% for {, %> for }, <: for [ and :> for ] (C99)
" But avoid matching <::.
syn cluster     cParenGroup     contains=cParenError,cIncluded,cSpecial,cCommentSkip,cCommentString,cComment2String,@cCommentGroup,cCommentStartError,cUserLabel,cBitField,cOctalZero,@cCppOutInGroup,cFormat,cNumber,cFloat,cOctal,cOctalError,cNumbersCom
if exists("c_no_curly_error")
    if s:in_cpp_family && !exists("cpp_no_cpp11")
        syn region  cParen          transparent start='(' end=')' contains=ALLBUT,@cParenGroup,cCppParen,@cStringGroup,@Spell
        " cCppParen: same as cParen but ends at end-of-line; used in cDefine
        syn region  cCppParen       transparent start='(' skip='\\$' excludenl end=')' end='$' contained contains=ALLBUT,@cParenGroup,cParen,cString,@Spell
        syn match   cParenError     display ")"
        syn match   cErrInParen     display contained "^^<%\|^%>"
    else
        syn region  cParen          transparent start='(' end=')' contains=ALLBUT,cBlock,@cParenGroup,cCppParen,@cStringGroup,@Spell
        " cCppParen: same as cParen but ends at end-of-line; used in cDefine
        syn region  cCppParen       transparent start='(' skip='\\$' excludenl end=')' end='$' contained contains=ALLBUT,@cParenGroup,cParen,cString,@Spell
        syn match   cParenError     display ")"
        syn match   cErrInParen     display contained "^[{}]\|^<%\|^%>"
    endif
elseif exists("c_no_bracket_error")
    if s:in_cpp_family && !exists("cpp_no_cpp11")
        syn region  cParen          transparent start='(' end=')' contains=ALLBUT,@cParenGroup,cCppParen,@cStringGroup,@Spell
        " cCppParen: same as cParen but ends at end-of-line; used in cDefine
        syn region  cCppParen       transparent start='(' skip='\\$' excludenl end=')' end='$' contained contains=ALLBUT,@cParenGroup,cParen,cString,@Spell
        syn match   cParenError     display ")"
        syn match   cErrInParen     display contained "<%\|%>"
    else
        syn region  cParen          transparent start='(' end=')' end='}'me=s-1 contains=ALLBUT,cBlock,@cParenGroup,cCppParen,@cStringGroup,@Spell
        " cCppParen: same as cParen but ends at end-of-line; used in cDefine
        syn region  cCppParen       transparent start='(' skip='\\$' excludenl end=')' end='$' contained contains=ALLBUT,@cParenGroup,cParen,cString,@Spell
        syn match   cParenError     display ")"
        syn match   cErrInParen     display contained "[{}]\|<%\|%>"
    endif
else
    if s:in_cpp_family && !exists("cpp_no_cpp11")
        syn region  cParen          transparent start='(' end=')' contains=ALLBUT,@cParenGroup,cCppParen,cErrInBracket,cCppBracket,@cStringGroup,@Spell
        " cCppParen: same as cParen but ends at end-of-line; used in cDefine
        syn region  cCppParen       transparent start='(' skip='\\$' excludenl end=')' end='$' contained contains=ALLBUT,@cParenGroup,cErrInBracket,cParen,cBracket,cString,@Spell
        syn match   cParenError     display "[\])]"
        syn match   cErrInParen     display contained "<%\|%>"
        syn region  cBracket        transparent start='\[\|<::\@!' end=']\|:>' contains=ALLBUT,@cParenGroup,cErrInParen,cCppParen,cCppBracket,@cStringGroup,@Spell
    else
        syn region  cParen          transparent start='(' end=')' end='}'me=s-1 contains=ALLBUT,cBlock,@cParenGroup,cCppParen,cErrInBracket,cCppBracket,@cStringGroup,@Spell
        " cCppParen: same as cParen but ends at end-of-line; used in cDefine
        syn region  cCppParen       transparent start='(' skip='\\$' excludenl end=')' end='$' contained contains=ALLBUT,@cParenGroup,cErrInBracket,cParen,cBracket,cString,@Spell
        syn match   cParenError     display "[\])]"
        syn match   cErrInParen     display contained "[\]{}]\|<%\|%>"
        syn region  cBracket        transparent start='\[\|<::\@!' end=']\|:>' end='}'me=s-1 contains=ALLBUT,cBlock,@cParenGroup,cErrInParen,cCppParen,cCppBracket,@cStringGroup,@Spell
    endif
    " cCppBracket: same as cParen but ends at end-of-line; used in cDefine
    syn region    cCppBracket     transparent start='\[\|<::\@!' skip='\\$' excludenl end=']\|:>' end='$' contained contains=ALLBUT,@cParenGroup,cErrInParen,cParen,cBracket,cString,@Spell
    syn match     cErrInBracket   display contained "[);{}]\|<%\|%>"
endif

if s:ft ==# 'c' || exists("cpp_no_cpp11")
    syn region    cBadBlock
    \ transparent
    \ keepend
    \ start="{"
      \ end="}"
    \ contained   containedin=cParen,cBracket,cBadBlock
    \ fold
endif

"integer number, or floating point number without a dot and with "f".
syn case ignore
syn match       cNumbers        display transparent "\<\d\|\.\d" contains=cNumber,cFloat,cOctalError,cOctal
" Same, but without octal error (for comments)
syn match       cNumbersCom     display contained transparent "\<\d\|\.\d" contains=cNumber,cFloat,cOctal
syn match       cNumber         display contained "\d\+\(u\=l\{0,2}\|ll\=u\)\>"
"hex number
syn match       cNumber         display contained "0x\x\+\(u\=l\{0,2}\|ll\=u\)\>"
" Flag the first zero of an octal number as something special
syn match       cOctal          display contained "0\o\+\(u\=l\{0,2}\|ll\=u\)\>" contains=cOctalZero
syn match       cOctalZero      display contained "\<0"
"floating point number, with dot, optional exponent
syn match       cFloat          display contained "\d\+\.\d*\(e[-+]\=\d\+\)\=[fl]\="
"floating point number, starting with a dot, optional exponent
syn match       cFloat          display contained "\.\d\+\(e[-+]\=\d\+\)\=[fl]\=\>"
"floating point number, without dot, with exponent
syn match       cFloat          display contained "\d\+e[-+]\=\d\+[fl]\=\>"
if !exists("c_no_c99")
    "hexadecimal floating point number, optional leading digits, with dot, with exponent
    syn match     cFloat          display contained "0x\x*\.\x\+p[-+]\=\d\+[fl]\=\>"
    "hexadecimal floating point number, with leading digits, optional dot, with exponent
    syn match     cFloat          display contained "0x\x\+\.\=p[-+]\=\d\+[fl]\=\>"
endif

" flag an octal number with wrong digits
syn match       cOctalError     display contained "0\o*[89]\d*"
syn case match

"\ comment
syn match cHead_of_CommentL #// #  conceal contained containedin=cCommentL
syn match cHead_of_CommentL #//\s*$#  conceal contained containedin=cCommentL
    if exists("c_comment_strings")
        " A comment can contain cString, cCharacter and cNumber.
        " But a "*/" inside
            " a cString  in a cComment
            " does end the comment!
        " So we  need to use a special type of cString:
            " cCommentString,
                " which also ends on  "*/",
                " and sees a "*" at the start of the line as comment again.
        " Unfortunately this doesn't very well work for // type of comments
        syn match     cCommentSkip
                \ contained
                \ "^\s*\*\($\|\s\+\)"

        syn region cCommentString
                \ start=+L\=\\\@<!"+
                \ skip=+\\\\\|\\"+
                \ end=+"+
                \ end=+\*/+me=s-1
            \ contained
            \ contains=cSpecial,cCommentSkip

        syn region cComment2String
        \ start=+L\=\\\@<!"+
            \ skip=+\\\\\|\\"+
        \ end=+"+
        \ end="$"
        \ contained   contains=cSpecial

        syn region  cCommentL
        \ start="//"
        \ skip="\\$"
        \ end="$"
        \ keepend
        \ contains=@cCommentGroup,
            \cComment2String,
            \cCharacter,
            \cNumbersCom,
            \cSpaceError,
            \cWrongComTail,
            \@Spell

        if exists("c_no_comment_fold")
            " Use "extend" here to have
            " preprocessor lines
            " not terminate halfway a  comment.
            syn region cComment
                \ matchgroup=cCommentStart
                \ start="/\*"
                \ end="\*/"
                \ contains=@cCommentGroup,
                        \cCommentStartError,
                        \cCommentString,
                        \cCharacter,
                        \cNumbersCom,
                        \cSpaceError,
                        \@Spell
            \ extend
        else
            syn region cComment
                \ matchgroup=cCommentStart
                \ start="/\*"
                \ end="\*/"
                \ contains=@cCommentGroup,
                        \cCommentStartError,
                        \cCommentString,
                        \cCharacter,
                        \cNumbersCom,
                        \cSpaceError,
                        \@Spell
                \ fold
                \ extend
        endif
    else
        syn region   cCommentL
                    \ start="//"
                    \ skip="\\$"
                    \ end="$"
                    \ keepend
                    \ contains=@cCommentGroup,cSpaceError,@Spell

        if exists("c_no_comment_fold")
            syn region  cComment
            \ matchgroup=cCommentStart
            \ start="/\*"
            \ end="\*/"
            \ contains=@cCommentGroup,
                    \cCommentStartError,
                    \cSpaceError,
                    \@Spell
            \ extend
        else
            syn region  cComment
            \ matchgroup=cCommentStart
            \ start="/\*"
            \ end="\*/"
            \ contains=@cCommentGroup,
                    \cCommentStartError,
                    \cSpaceError,
                    \@Spell
            \ extend
            \ fold
        endif
    endif
    " keep a // comment separately,
    " it terminates a preproc. conditional
        syn   match   cCommentError        display   "\*/"
        syn   match   cCommentStartError   display   "/\*"me=e-1   contained
        syn   match   cWrongComTail        display   "\*/"

syn keyword     cOperator       sizeof

if exists("c_gnu")
    syn keyword   cType           __label__ __complex__
    syn keyword   cStatement      __asm__
    syn keyword   cOperator       __alignof__
    syn keyword   cOperator       typeof __typeof__
    syn keyword   cOperator       __real__ __imag__
    syn keyword   cStorageClass   __attribute__ __const__ __extension__
    syn keyword   cStorageClass   inline __inline__
    syn keyword   cStorageClass   __restrict__ __volatile__ __noreturn__
endif
syn keyword     cType           int long short char void
syn keyword     cType           signed unsigned float double
if !exists("c_no_ansi") || exists("c_ansi_typedefs")
    syn keyword   cType           size_t ssize_t off_t wchar_t ptrdiff_t sig_atomic_t fpos_t
    syn keyword   cType           clock_t time_t va_list jmp_buf FILE DIR div_t ldiv_t
    syn keyword   cType           mbstate_t wctrans_t wint_t wctype_t
endif
if !exists("c_no_c99") " ISO C99
    syn keyword   cType           _Bool bool _Complex complex _Imaginary imaginary
    syn keyword   cType           int8_t int16_t int32_t int64_t
    syn keyword   cType           uint8_t uint16_t uint32_t uint64_t
    if !exists("c_no_bsd")
        " These are BSD specific.
        syn keyword cType           u_int8_t u_int16_t u_int32_t u_int64_t
    endif
    syn keyword   cType           int_least8_t int_least16_t int_least32_t int_least64_t
    syn keyword   cType           uint_least8_t uint_least16_t uint_least32_t uint_least64_t
    syn keyword   cType           int_fast8_t int_fast16_t int_fast32_t int_fast64_t
    syn keyword   cType           uint_fast8_t uint_fast16_t uint_fast32_t uint_fast64_t
    syn keyword   cType           intptr_t uintptr_t
    syn keyword   cType           intmax_t uintmax_t
endif

syn keyword     cTypedef        typedef
syn keyword     cStructure      struct union enum
syn keyword     cStorageClass   static register auto volatile extern const
if !exists("c_no_c99") && !s:in_cpp_family
    syn keyword   cStorageClass   inline restrict
endif
if !exists("c_no_c11")
    syn keyword   cStorageClass   _Alignas alignas
    syn keyword   cOperator       _Alignof alignof
    syn keyword   cStorageClass   _Atomic
    syn keyword   cOperator       _Generic
    syn keyword   cStorageClass   _Noreturn noreturn
    syn keyword   cOperator       _Static_assert static_assert
    syn keyword   cStorageClass   _Thread_local thread_local
    syn keyword   cType           char16_t char32_t
    syn keyword   cType           max_align_t
    " C11 atomics (take down the shield wall!)
    syn keyword   cType           atomic_bool atomic_char atomic_schar atomic_uchar
    syn keyword   Ctype           atomic_short atomic_ushort atomic_int atomic_uint
    syn keyword   cType           atomic_long atomic_ulong atomic_llong atomic_ullong
    syn keyword   cType           atomic_char16_t atomic_char32_t atomic_wchar_t
    syn keyword   cType           atomic_int_least8_t atomic_uint_least8_t
    syn keyword   cType           atomic_int_least16_t atomic_uint_least16_t
    syn keyword   cType           atomic_int_least32_t atomic_uint_least32_t
    syn keyword   cType           atomic_int_least64_t atomic_uint_least64_t
    syn keyword   cType           atomic_int_fast8_t atomic_uint_fast8_t
    syn keyword   cType           atomic_int_fast16_t atomic_uint_fast16_t
    syn keyword   cType           atomic_int_fast32_t atomic_uint_fast32_t
    syn keyword   cType           atomic_int_fast64_t atomic_uint_fast64_t
    syn keyword   cType           atomic_intptr_t atomic_uintptr_t
    syn keyword   cType           atomic_size_t atomic_ptrdiff_t
    syn keyword   cType           atomic_intmax_t atomic_uintmax_t
endif

if !exists("c_no_ansi") || exists("c_ansi_constants") || exists("c_gnu")
    if exists("c_gnu")
        syn keyword cConstant __GNUC__ __FUNCTION__ __PRETTY_FUNCTION__ __func__
    endif
    syn keyword cConstant __LINE__ __FILE__ __DATE__ __TIME__ __STDC__ __STDC_VERSION__ __STDC_HOSTED__
    syn keyword cConstant CHAR_BIT MB_LEN_MAX MB_CUR_MAX
    syn keyword cConstant UCHAR_MAX UINT_MAX ULONG_MAX USHRT_MAX
    syn keyword cConstant CHAR_MIN INT_MIN LONG_MIN SHRT_MIN
    syn keyword cConstant CHAR_MAX INT_MAX LONG_MAX SHRT_MAX
    syn keyword cConstant SCHAR_MIN SINT_MIN SLONG_MIN SSHRT_MIN
    syn keyword cConstant SCHAR_MAX SINT_MAX SLONG_MAX SSHRT_MAX
    if !exists("c_no_c99")
        syn keyword cConstant __func__ __VA_ARGS__
        syn keyword cConstant LLONG_MIN LLONG_MAX ULLONG_MAX
        syn keyword cConstant INT8_MIN INT16_MIN INT32_MIN INT64_MIN
        syn keyword cConstant INT8_MAX INT16_MAX INT32_MAX INT64_MAX
        syn keyword cConstant UINT8_MAX UINT16_MAX UINT32_MAX UINT64_MAX
        syn keyword cConstant INT_LEAST8_MIN INT_LEAST16_MIN INT_LEAST32_MIN INT_LEAST64_MIN
        syn keyword cConstant INT_LEAST8_MAX INT_LEAST16_MAX INT_LEAST32_MAX INT_LEAST64_MAX
        syn keyword cConstant UINT_LEAST8_MAX UINT_LEAST16_MAX UINT_LEAST32_MAX UINT_LEAST64_MAX
        syn keyword cConstant INT_FAST8_MIN INT_FAST16_MIN INT_FAST32_MIN INT_FAST64_MIN
        syn keyword cConstant INT_FAST8_MAX INT_FAST16_MAX INT_FAST32_MAX INT_FAST64_MAX
        syn keyword cConstant UINT_FAST8_MAX UINT_FAST16_MAX UINT_FAST32_MAX UINT_FAST64_MAX
        syn keyword cConstant INTPTR_MIN INTPTR_MAX UINTPTR_MAX
        syn keyword cConstant INTMAX_MIN INTMAX_MAX UINTMAX_MAX
        syn keyword cConstant PTRDIFF_MIN PTRDIFF_MAX SIG_ATOMIC_MIN SIG_ATOMIC_MAX
        syn keyword cConstant SIZE_MAX WCHAR_MIN WCHAR_MAX WINT_MIN WINT_MAX
    endif
    syn keyword cConstant FLT_RADIX FLT_ROUNDS FLT_DIG FLT_MANT_DIG FLT_EPSILON DBL_DIG DBL_MANT_DIG DBL_EPSILON
    syn keyword cConstant LDBL_DIG LDBL_MANT_DIG LDBL_EPSILON FLT_MIN FLT_MAX FLT_MIN_EXP FLT_MAX_EXP FLT_MIN_10_EXP FLT_MAX_10_EXP
    syn keyword cConstant DBL_MIN DBL_MAX DBL_MIN_EXP DBL_MAX_EXP DBL_MIN_10_EXP DBL_MAX_10_EXP LDBL_MIN LDBL_MAX LDBL_MIN_EXP LDBL_MAX_EXP
    syn keyword cConstant LDBL_MIN_10_EXP LDBL_MAX_10_EXP HUGE_VAL CLOCKS_PER_SEC NULL LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY
    syn keyword cConstant LC_NUMERIC LC_TIME SIG_DFL SIG_ERR SIG_IGN SIGABRT SIGFPE SIGILL SIGHUP SIGINT SIGSEGV SIGTERM
    " Add POSIX signals as well...
    syn keyword cConstant SIGABRT SIGALRM SIGCHLD SIGCONT SIGFPE SIGHUP SIGILL SIGINT SIGKILL SIGPIPE SIGQUIT SIGSEGV
    syn keyword cConstant SIGSTOP SIGTERM SIGTRAP SIGTSTP SIGTTIN SIGTTOU SIGUSR1 SIGUSR2
    syn keyword cConstant _IOFBF _IOLBF _IONBF BUFSIZ EOF WEOF FOPEN_MAX FILENAME_MAX L_tmpnam
    syn keyword cConstant SEEK_CUR SEEK_END SEEK_SET TMP_MAX stderr stdin stdout EXIT_FAILURE EXIT_SUCCESS RAND_MAX
    " used in assert.h
    syn keyword cConstant NDEBUG
    " POSIX 2001
    syn keyword cConstant SIGBUS SIGPOLL SIGPROF SIGSYS SIGURG SIGVTALRM SIGXCPU SIGXFSZ
    " non-POSIX signals
    syn keyword cConstant SIGWINCH SIGINFO
    " Add POSIX errors as well.  List comes from:
    " http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
    syn keyword cConstant
                    \ E2BIG
                    \ EACCES
                    \ EADDRINUSE
                    \ EADDRNOTAVAIL
                    \ EAFNOSUPPORT
                    \ EAGAIN
                    \ EALREADY
                    \ EBADF
                    \ EBADMSG
                    \ EBUSY
                    \ ECANCELED
                    \ ECHILD
                    \ ECONNABORTED
                    \ ECONNREFUSED
                    \ ECONNRESET
                    \ EDEADLK
                    \ EDESTADDRREQ
                    \ EDOM
                    \ EDQUOT
                    \ EEXIST
                    \ EFAULT
                    \ EFBIG
                    \ EHOSTUNREACH
                    \ EIDRM
                    \ EILSEQ
                    \ EINPROGRESS
                    \ EINTR
                    \ EINVAL
                    \ EIO
                    \ EISCONN
                    \ EISDIR
                    \ ELOOP
                    \ EMFILE
                    \ EMLINK
                    \ EMSGSIZE
                    \ EMULTIHOP
                    \ ENAMETOOLONG
                    \ ENETDOWN
                    \ ENETRESET
                    \ ENETUNREACH
                    \ ENFILE
                    \ ENOBUFS
                    \ ENODATA
                    \ ENODEV
                    \ ENOENT
                    \ ENOEXEC
                    \ ENOLCK
                    \ ENOLINK
                    \ ENOMEM
                    \ ENOMSG
                    \ ENOPROTOOPT
                    \ ENOSPC
                    \ ENOSR
                    \ ENOSTR
                    \ ENOSYS
                    \ ENOTBLK
                    \ ENOTCONN
                    \ ENOTDIR
                    \ ENOTEMPTY
                    \ ENOTRECOVERABLE
                    \ ENOTSOCK
                    \ ENOTSUP
                    \ ENOTTY
                    \ ENXIO
                    \ EOPNOTSUPP
                    \ EOVERFLOW
                    \ EOWNERDEAD
                    \ EPERM
                    \ EPIPE
                    \ EPROTO
                    \ EPROTONOSUPPORT
                    \ EPROTOTYPE
                    \ ERANGE
                    \ EROFS
                    \ ESPIPE
                    \ ESRCH
                    \ ESTALE
                    \ ETIME
                    \ ETIMEDOUT
                    \ ETXTBSY
                    \ EWOULDBLOCK
                    \ EXDEV
    " math.h
    syn keyword cConstant M_E M_LOG2E M_LOG10E M_LN2 M_LN10 M_PI M_PI_2 M_PI_4
    syn keyword cConstant M_1_PI M_2_PI M_2_SQRTPI M_SQRT2 M_SQRT1_2
endif
if !exists("c_no_c99") " ISO C99
    syn keyword cConstant true false
endif

" Accept %: for # (C99)
syn region      cPreCondit      start="^\s*\zs\(%:\|#\)\s*\(if\|ifdef\|ifndef\|elif\)\>" skip="\\$" end="$" keepend contains=cComment,cCommentL,cCppString,cCharacter,cCppParen,cParenError,cNumbers,cCommentError,cSpaceError
syn match       cPreConditMatch display "^\s*\zs\(%:\|#\)\s*\(else\|endif\)\>"
if !exists("c_no_if0")
    syn cluster   cCppOutInGroup  contains=cCppInIf,cCppInElse,cCppInElse2,cCppOutIf,cCppOutIf2,cCppOutElse,cCppInSkip,cCppOutSkip
    syn region    cCppOutWrapper  start="^\s*\zs\(%:\|#\)\s*if\s\+0\+\s*\($\|//\|/\*\|&\)" end=".\@=\|$" contains=cCppOutIf,cCppOutElse,@NoSpell fold
    syn region    cCppOutIf       contained start="0\+" matchgroup=cCppOutWrapper end="^\s*\(%:\|#\)\s*endif\>" contains=cCppOutIf2,cCppOutElse
    if !exists("c_no_if0_fold")
        syn region  cCppOutIf2      contained matchgroup=cCppOutWrapper start="0\+" end="^\s*\(%:\|#\)\s*\(else\>\|elif\s\+\(0\+\s*\($\|//\|/\*\|&\)\)\@!\|endif\>\)"me=s-1 contains=cSpaceError,cCppOutSkip,@Spell fold
    else
        syn region  cCppOutIf2      contained matchgroup=cCppOutWrapper start="0\+" end="^\s*\(%:\|#\)\s*\(else\>\|elif\s\+\(0\+\s*\($\|//\|/\*\|&\)\)\@!\|endif\>\)"me=s-1 contains=cSpaceError,cCppOutSkip,@Spell
    endif
    syn region    cCppOutElse     contained matchgroup=cCppOutWrapper start="^\s*\(%:\|#\)\s*\(else\|elif\)" end="^\s*\(%:\|#\)\s*endif\>"me=s-1 contains=TOP,cPreCondit
    syn region    cCppInWrapper   start="^\s*\zs\(%:\|#\)\s*if\s\+0*[1-9]\d*\s*\($\|//\|/\*\||\)" end=".\@=\|$" contains=cCppInIf,cCppInElse fold
    syn region    cCppInIf        contained matchgroup=cCppInWrapper start="\d\+" end="^\s*\(%:\|#\)\s*endif\>" contains=TOP,cPreCondit
    if !exists("c_no_if0_fold")
        syn region  cCppInElse      contained start="^\s*\(%:\|#\)\s*\(else\>\|elif\s\+\(0*[1-9]\d*\s*\($\|//\|/\*\||\)\)\@!\)" end=".\@=\|$" containedin=cCppInIf contains=cCppInElse2 fold
    else
        syn region  cCppInElse      contained start="^\s*\(%:\|#\)\s*\(else\>\|elif\s\+\(0*[1-9]\d*\s*\($\|//\|/\*\||\)\)\@!\)" end=".\@=\|$" containedin=cCppInIf contains=cCppInElse2
    endif
    syn region    cCppInElse2     contained matchgroup=cCppInWrapper start="^\s*\(%:\|#\)\s*\(else\|elif\)\([^/]\|/[^/*]\)*" end="^\s*\(%:\|#\)\s*endif\>"me=s-1 contains=cSpaceError,cCppOutSkip,@Spell
    syn region    cCppOutSkip     contained start="^\s*\(%:\|#\)\s*\(if\>\|ifdef\>\|ifndef\>\)" skip="\\$" end="^\s*\(%:\|#\)\s*endif\>" contains=cSpaceError,cCppOutSkip
    syn region    cCppInSkip      contained matchgroup=cCppInWrapper start="^\s*\(%:\|#\)\s*\(if\s\+\(\d\+\s*\($\|//\|/\*\||\|&\)\)\@!\|ifdef\>\|ifndef\>\)" skip="\\$" end="^\s*\(%:\|#\)\s*endif\>" containedin=cCppOutElse,cCppInIf,cCppInSkip contains=TOP,cPreProc
endif
syn region      cIncluded       display contained start=+"+ skip=+\\\\\|\\"+ end=+"+
syn match       cIncluded       display contained "<[^>]*>"
syn match       cInclude        display "^\s*\zs\(%:\|#\)\s*include\>\s*["<]" contains=cIncluded
"syn match cLineSkip    "\\$"
syn cluster     cPreProcGroup
                    \ contains=cPreCondit,
                      \cIncluded,
                      \cInclude,
                      \cDefine,
                      \cErrInParen,
                      \cErrInBracket,
                      \cUserLabel,
                      \cSpecial,
                      \cOctalZero,
                      \cCppOutWrapper,
                      \cCppInWrapper,
                      \@cCppOutInGroup,
                      \cFormat,
                      \cNumber,
                      \cFloat,
                      \cOctal,
                      \cOctalError,
                      \cNumbersCom,
                      \cString,
                      \cCommentSkip,
                      \cCommentString,
                      \cComment2String,
                      \@cCommentGroup,
                      \cCommentStartError,
                      \cParen,
                      \cBracket,
                      \cMulti,
                      \cBadBlock

syn region   cDefine
                \ start="^\s*\zs\(%:\|#\)\s*\(define\|undef\)\>"
                \ skip="\\$"
                \ end="$"
                \ keepend
                \ contains=ALLBUT,@cPreProcGroup,@Spell

syn region   cPreProc
               \ keepend
               \ start="^\s*\zs\(%:\|#\)\s*\(pragma\>\|line\>\|warning\>\|warn\>\|error\>\)"
               \ skip="\\$"
                 \ end="$"
               \ contains=ALLBUT,@cPreProcGroup,@Spell

" Optional embedded Autodoc parsing
if exists("c_autodoc")
    syn match cAutodocReal display contained "\%(//\|[/ \t\v]\*\|^\*\)\@2<=!.*" contains=@cAutodoc containedin=cComment,cCommentL
    syn cluster cCommentGroup add=cAutodocReal
    syn cluster cPreProcGroup add=cAutodocReal
endif

" be able to fold #pragma regions
syn region      cPragma         start="^\s*#pragma\s\+region\>" end="^\s*#pragma\s\+endregion\>" transparent keepend extend fold

" Highlight User Labels
syn cluster     cMultiGroup     contains=cIncluded,cSpecial,cCommentSkip,cCommentString,cComment2String,@cCommentGroup,cCommentStartError,cUserCont,cUserLabel,cBitField,cOctalZero,cCppOutWrapper,cCppInWrapper,@cCppOutInGroup,cFormat,cNumber,cFloat,cOctal,cOctalError,cNumbersCom,cCppParen,cCppBracket,cCppString
if s:ft ==# 'c' || exists("cpp_no_cpp11")
    syn region    cMulti          transparent start='?' skip='::' end=':' contains=ALLBUT,@cMultiGroup,@Spell,@cStringGroup
endif
" Avoid matching foo::bar() in C++ by requiring that the next char is not ':'
syn cluster     cLabelGroup     contains=cUserLabel
syn match       cUserCont       display "^\s*\zs\I\i*\s*:$" contains=@cLabelGroup
syn match       cUserCont       display ";\s*\zs\I\i*\s*:$" contains=@cLabelGroup
if s:in_cpp_family
    syn match     cUserCont       display "^\s*\zs\%(class\|struct\|enum\)\@!\I\i*\s*:[^:]"me=e-1 contains=@cLabelGroup
    syn match     cUserCont       display ";\s*\zs\%(class\|struct\|enum\)\@!\I\i*\s*:[^:]"me=e-1 contains=@cLabelGroup
else
    syn match     cUserCont       display "^\s*\zs\I\i*\s*:[^:]"me=e-1 contains=@cLabelGroup
    syn match     cUserCont       display ";\s*\zs\I\i*\s*:[^:]"me=e-1 contains=@cLabelGroup
endif

syn match       cUserLabel      display "\I\i*" contained

" Avoid recognizing most bitfields as labels
syn match       cBitField       display "^\s*\zs\I\i*\s*:\s*[1-9]"me=e-1 contains=cType
syn match       cBitField       display ";\s*\zs\I\i*\s*:\s*[1-9]"me=e-1 contains=cType

if exists("c_minlines")
    let b:c_minlines = c_minlines
else
    if !exists("c_no_if0")
        let b:c_minlines = 50       " #if 0 constructs can be long
    else
        let b:c_minlines = 15       " mostly for () constructs
    endif
endif
if exists("c_curly_error")
    syn sync fromstart
else
    exec "syn sync ccomment cComment minlines=" . b:c_minlines
endif

" Define the default highlighting.
" Only used when an item doesn't have highlighting yet
hi def link cFormat             cSpecial
hi def link cCppString          cString

hi def link cCommentL           cComment
hi def link cCommentStart       HidE
    "\ hi def link cCommentStart       cComment
    "\ 不行:
    "\ au My_syn Syntax   c          syn match c_com_start '/\* '
    "\         \ contained conceal containedin=cCommentString,cCommentString2
    "\
    "\ au My_syn Syntax   c          syn match c_com_end ' \*/'
    "\         \ contained conceal containedin=cCommentString,cCommentString2


hi def link cLabel              Label
hi def link cUserLabel          Label
hi def link cConditional        Conditional
hi def link cRepeat             Repeat
hi def link cCharacter          Character
hi def link cSpecialCharacter   cSpecial
hi def link cNumber             Number
hi def link cOctal              Number
hi def link cOctalZero          PreProc  " link this to Error if you want
hi def link cFloat              Float
hi def link cOctalError         cError
hi def link cParenError         cError
hi def link cErrInParen         cError
hi def link cErrInBracket       cError
hi def link cCommentError       cError
hi def link cCommentStartError  cError
hi def link cSpaceError         cError
hi def link cWrongComTail       cError
hi def link cSpecialError       cError
hi def link cCurlyError         cError
hi def link cOperator           Operator
hi def link cStructure          Structure
hi def link cTypedef            Structure
hi def link cStorageClass       StorageClass
hi def link cInclude            Include
hi def link cPreProc            PreProc
hi def link cDefine             Macro
hi def link cIncluded           cString
hi def link cError              Error
hi def link cStatement          Statement
hi def link cCppInWrapper       cCppOutWrapper
hi def link cCppOutWrapper      cPreCondit
hi def link cPreConditMatch     cPreCondit
hi def link cPreCondit          PreCondit
hi def link cType               Type
hi def link cConstant           Constant
hi def link cCommentString      cString
hi def link cComment2String     cString
hi def link cCommentSkip        cComment
hi def link cString             String
hi def link cComment            Comment
hi def link cSpecial            SpecialChar
hi def link cTodo               Todo
hi def link cBadContinuation    Error
hi def link cCppOutSkip         cCppOutIf2
hi def link cCppInElse2         cCppOutIf2
hi def link cCppOutIf2          cCppOut
hi def link cCppOut             Comment

let b:current_syntax = "c"

unlet s:ft

let &cpo = s:cpo_save
unlet s:cpo_save
